Status of NuMIMINOS

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Status of NuMI/MINOS
Mark Thomson University of Cambridge
This talk

• Overview
• NuMI Beam
• MINOS Far and Near Detectors
• Physics Capabilities
• First Data
• - cosmic muons
• - atmospheric ns

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MINOS Basic Idea
735 km
Measure ratio of neutrino energy spectrum in far
detector (oscillated) to that in the near
detector (unoscillated)
Partial cancellation of systematics
Near (unosc)
Far (oscillated)
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MINOS Physics Goals
Demonstrate oscillation behaviour

• confirm flavour oscillations describe data

• provide high statistics discrimination against
• alternative models
• decoherence, n decay, extra dimensions,
  etc.

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The NuMI beam

• 120 GeV protons extracted from the MAIN
• INJECTOR in a single turn (8.7ms)
• 1.9 s cycle time
• i.e. n beam on for 8.7ms every 1.9 s
• 2.5x1013 protons/pulse
• 0.3 MW on target !
• Initial intensity
• 2.5x1020 protons/year

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Tunable beam

• Relative positions of the
• neutrino horns allow beam
• energy to be tuned. Act like a
• pair of (highly achromatic lenses)
• Start with LE beam best for __Dm20.002 eV2

LE BEAM
Low Medium High
1600 4300 9250
(2.5x1020 protons on target/year)
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The NuMI n beam I
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The NuMI n beam II
Steep incline
Carrier tunnel
Pre-target

• Beam points 3.3o
• downwards

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The NuMI n beam III
p

• Horn pulsed with 200 kA
• Toroidal Magnetic field B I/r between
• inner and outer conducters

p
p
p
I
I
B
?
I
p-
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The NuMI n beam IV
p
Shielding Installation
Before shielding
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The NuMI n beam V
p
n
675 m long decay pipe

• Need long decay pipe
• for a 5 GeV p
• gct 200 m
• Evacuated to 1.5 Torr
• Steel decay pipe installed
• and encased in 2-3 m of
• concrete to protect
• ground water

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Going underground
2070 mwe
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MINOS Far Detector

• 8m octagonal steel scintillator tracking
  calorimeter
• 2 sections, 15m each
• 5.4 kton total mass
• 55/?E for hadrons
• 23/?E for electrons
• Magnetized Iron (B1.5T)
• 484 planes of scintillator

One Supermodule of the Far Detector Two
Supermodules total.
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Detector Elements

• Steel-Scintillator sandwich SAMPLING
  CALORIMETER
• Each plane consists of a 2.54 cm steel 1 cm
  scintillator
• Each scintillator plane divided into 192 x 4cm
  wide strips
• Alternate planes have orthogonal strip
  orientations (U and V)

• Scintillation light collected by
• WLS fibre glued into groove
• Readout by multi-pixel PMTs

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MINOS FarDet during installation
Electronics Racks
SM 1
SM 2
Optical Fibre Read out
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Far Detector fully operational since July 2003
Veto Shield
Coil
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Event Information

• Two 2D views of event

• Software combination to get 3D event

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B-Field
1.5 T Magnetic Field

• Charge separation

• Momentum measurement

UZ
VZ
time
PEs
Stopping muon Prange 3.86 GeV/c Pcurvature
4.03 GeV/c
Single Hit Resolution 2.5 ns
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MINOS Near Detector

• 1 kton total mass
• Same basic design
• steel, scintillator, etc
• Some differences, e.g

Faster electronics Partially instrumented
282 planes of steel 153 planes of
scintillator (Rear part of detector
only used to track muons ) ..
Currently being installed at Fermilab
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MINOS Beam Physics (MC)
UZ
NC Event
n

• often
• diffuse

VZ

• m track

• hadronic
• activity

• compact
• shower

• typical EM
• shower
• profile

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Test Beam
Response measured in CERN test beam using a
MINI-MINOS

• Provides calibration information
• Test of MC simulation of low energy hadronic
  interactions

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MINOS Physics Sensitivity

• Measurement of Dm2 and sin22q

For Dm2 0.0025 eV2, sin2 2q 1.0
Large improvement in precision !
Final sensitivity depends on protons on target

• Direct measurement of L/E dependence of nm flux
• Powerful test of flavour oscillations vs.
  alternative
• models

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ne Appearance
Dm2 0.0025 eV2
for Dm2 0.0025 eV2
MINOS 3s Discovery Limits

• 3 s discovery potential may significantly eat
  into current
• allowed region exact reach depends on
  protons on target

• reasonable chance of making the first
  measurement of q13 !

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First beam in December 2004
BUT Already Have Data....
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Moon Shadow
HE primary cosmic rays shadowed by moon
Not to scale

• Have recorded 10 M cosmic muons
• observed shadow of moon
• Angular res. improved by selecting high momenta
  muons

(less multiple scattering)
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n induced upward m

• Expect 1 Event/6 Days
• Identified on basis of timing

UZ
Earliest hits
VZ
time
PEs
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n induced upward-going muons

• Look for events coming from below horizon
• Require clear up/down resolution from timing

• Good track gt 2.0 m
• gt20 planes crossed

• Calculate muon velocity from hit times b v/c

• Clear separation of
• up/down going ms !

s1/b 0.05

• 48 Upward events

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Upward m Analysis Data vs. MC

• NUANCE generator
• Bartol 96 flux
• MC normalised to data
• (assuming no oscillations)

• Charge-tagging
• Tag n/n using muon charge
• Efficiency depends on
• - muon momentum
• - track length
• - orientation wrt B-field
• Clean charge ID for
• approx. 50 of events

• Understanding systematics Work in progress

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Contained Events

• MINOS Designed for ns from FNAL not
  atmospherics
• Gaps between planes - potentially problematic

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Contained Event Selection

• Signal/Noise (cosmics) 1/200,000
• Veto Shield helps efficiency 97
• Have achieved rejection factor of 110,000,000
  !
• Efficiency 75 with 98 purity

CC nm EVENT SELECTION

• Fiducial Volume
• little activity within 50cm of
• detector edge
• Reconstructed muon track
• track which crosses 8 planes
• Cosmic muon rejection
• remove steep events
• Veto Shield
• noin-time Veto shield hit

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Contained Event Selection
UZ
Data
VZ
time
PEs
Measure cosmic m bgd. from data using events
solely rejected on basis of veto hit
MINOS Preliminary
Vetoed background agrees with MC expectation !
n MC Battistoni et al
Does not include acceptance systematic
uncertainties work in progress
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Event Distributions

• En Em Ehad

• MC normalised to data
• (no oscillations)

• Cosmic background from data
• - from no. of vetoed events

n
Above
q
Below
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Charge Reconstruction
Tag n/n using muon curvature

• Curvature ? Q/p
• Select on basis of (Q/p)/sQ/p
• Pure charge ID for 70
• of selected events

MINOS atmos n analysis underway ! just need
more data
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Conclusions
NuMI beam installation progressing well !
expect first protons on target December 2004 !
MINOS Near Detector currently being installed/
commisioned at FermiLab
MINOS Far Detector taking physics quality
data since mid-2003
Atmospheric ns already being seen in the MINOS
Far Detector
First direct observation of n/n
separated atmospheric neutrinos
Eagerly awaiting first beam physics data,
expected early 2005 ! Exciting times for MINOS.
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MINOS en France